Synergistic effects of quaternary ammonium compounds and food additive grade calcium hydroxide on microbicidal activities at low temperatures

Abstract

The microbicidal activities of mixtures of quaternary ammonium compounds (QACs) and food additive grade calcium hydroxide (FdCa(OH)2) were evaluated in a suspension test at -20°C using an anti-freeze agent (AFA) containing methanol, or at 1°C, with varying contact time, toward avian influenza virus (AIV), Newcastle disease virus (NDV), fowl adenovirus (FAdV), avian reovirus (ARV), Salmonella Infantis (SI) and Escherichia coli (EC). At -20°C, the mixtures could inactivate AIV and NDV within 30 min, FAdV and ARV within 5 sec, and SI and EC within 3 min, respectively. AFA did not inactivate viruses and bacteria within 30 minutes and 10 minutes, respectively. At 1°C, the mixtures inactivated FAdV and ARV within 30 sec, AIV w i t h i n 1 0 m i n , a n d NDV w i t h i n 30 min. A mixture of slaked lime (SL) a n d QAC could inactivate FAdV and ARV within 30 sec, but could not inactivate AIV and NDV even after 60 min at 1°C. SL could not substitute FdCa(OH)2 in order to exert the synergistic effects with QAC. Thus, QACs microbicidal activities were maintained or enhanced by adding FdCa(OH)2. It is hence recommended to use QACs with FdCa(OH)2, especially in the winter season.

Evaluation of Virucidal Quantitative Carrier Test towards Bovine Viruses for Surface Disinfectants While Simulating Practical Usage on Livestock Farms

“…As shown in Table 1 , QACx500 failed to inactivate RVA in the suspension test, as well as infectious bursal disease virus (IBDV) (non-enveloped virus) as described [ 17 ]. Mix500 has a broad spectrum virucidal effect, resulting in a more effective virucidal agent, with a wide spectrum of pathogen inactivation [ 4 , 16 , 17 ]. Therefore, Mix500, the mixture of QAC and FdCa(OH) 2 , was selected for the carrier tests.…”

“…It is important to select disinfectants that are effective against a wide spectrum of pathogens under the conditions normally found on livestock farms. Mix500 can be applied as a disinfectant or a microbiocidal agent which can inactivate enveloped and non-enveloped viruses and bacteria in contaminated fomites, especially in mammals and poultry farms [ 1 , 4 , 16 , 17 ]. In Japan, the Ministry of Agriculture, Forestry and Fisheries (MAFF) recommends farmers to use agricultural slaked lime with a Ca(OH) 2 content of 65–75% for the enforcement of biosecurity measures; however, slaked lime failed to show synergistic effects with QAC toward AIV and NDV at low temperatures [ 16 ].…”

“…The QAC (Rontect ® ) was purchased from Scientific Feed Laboratory Co., Ltd. (Tokyo, Japan) and diluted 1:500 (QACx500) with redistilled water (dW 2 ), to obtain a final concentration of 200 ppm didecyl-dimethylammonium chloride (DDAC), as recommended by the manufacturer. FdCa(OH) 2 powder at pH 13 with an average diameter of 10 μm of powder particles [ 14 ] was purchased from Fine Co., Ltd. (Tokyo, Japan) and used as 0.17% FdCa(OH) 2 solution or as a QAC and FdCa(OH) 2 mixture (Mix500) [ 16 , 17 ].…”

“…Quaternary ammonium compounds (QACs) are commonly used at livestock farms, but their effectiveness is reduced by organic contamination and low temperatures [ 15 ]. However, QAC disinfection efficacy is synergistically enhanced even at low temperatures and in the presence of organic matter by adding FdCa(OH) 2 [ 16 , 17 ]. The synergism may be explained by Ca(OH) 2 ’s alkalinity that destructs cytoplasmic phospholipid membranes, thereby affecting the integrity of the cytoplasmic membrane [ 1 , 17 ].…”

Rapid in vitro virucidal activity of slightly acidic hypochlorous acid water toward aerosolized coronavirus in simulated human-dispersed droplets

“…The third area includes an air sampler consisted of a Rayon-polyester sheet (100 mm x 100 mm, Alphas R 5, Iwatsuki Co., Ltd., Tokyo, Japan), air bypass tubes, a bottle filled with a sterilizing agent and a suction pump (SP40, MARKOS-MEFAR, Bovezzo, Italy) equipped with HEPA filter. As a sterilizing agent, a mixture of quaternary ammonium compound (Rontect®, Scientific Feed Laboratory Co., Ltd., Tokyo, Japan) diluted 500 times, with 0.17% food additive grade calcium hydroxide (Fine Co., Ltd., Tokyo, Japan) was used, for preventing contamination by bioaerosols toward a suction pump, which passed air samples; its virucidal effect has been previously described ( Ito et al., 2018 ; Kabir et al., 2021 ; Miyaoka et al., 2021b ). The bottle filled with the mixture was connected to the suction pump providing an airflow rate of 35 L/min via an air bypass tube, without interrupting the airflow through the chamber.…”